In many electronic applications, it is necessary to store digital information permanently, securely and highly reliably. This requirement results from user or customer-specific necessity, where a program code is given by firmware and is stored in an NVM (non-volatile memory), for example. Further, data is often required (e.g., chip identification, customer version, skimming data for analog value adjustment (e.g., reference voltages, reference currents, switching thresholds, switching temperatures)), which may be programmed after manufacturing one time. It may be desired that the data is possibly burned in during the test procedure of a device or an application circuit and which cannot be erased or overwritten anymore. Some non-volatile memories integrated on chips are based on the method of one-time programming.
Such methods for programming non-volatile data on a chip one time can be based on PROM (programmable read-only memory), EEPROM (electrically erasable programmable read-only memory), flash memory or one-time programming devices (OTP), for example. The different methods are based on several physical mechanisms. For example, some are based on fusing. In this case, a lower resistive device structure is made open or highly resistive by an overcurrent impulse (e.g. poly fuse (open) metal fuse (open)). Another mechanism is based on laser fusing, which opens a low resistive connection by a laser cut. Further, also anti-fusing is one of these mechanisms. Here, a high resistive device structure is shortcut or made low resistive by an overvoltage or an overcurrent (e.g. oxide break (short), diode zapping (short)). Further, a one-time programming device may be based on an EEPROM or flash memory. In this case, the conductivity of an MOS-transistor (metal oxide semiconductor transistor) is defined by a deposited floating gate charge.